216 Steam Boiler Legislation. [April, 



by Watt, which was the favourite for more than forty years; 

 again followed the circular Cornish boiler used for pumping 

 engines, which for a number of years was worked at a 

 pressure of 30 to 40 lbs. on the square inch. These were 

 the pressures at which Cornish boilers were worked forty 

 years ago, but the extension of trade, and the demand for 

 increased pressure and increased power have produced great 

 changes. It was found that, in order to make an engine do 

 double the work, it was only necessary to double the pressure 

 and increase the velocity or number of strokes until the 

 required force was obtained. This was done with great 

 advantage as regards a saving of fuel, but not without risk ; 

 and thence ensued a continued series of break downs and boiler 

 explosions. These at one time became so frequent that 

 the writer was for several years summoned by coroners* 

 juries to investigate the causes of these disasters, and to 

 suggest remedies such as appeared necessary to reduce the 

 risk, and, if possible, to prevent the lamentable results of 

 boiler explosions. These enquiries ultimately led to the 

 formation of the Association above described, which since 

 that time to the present has been of great benefit to the 

 public. 



From the greatly increased and still increasing pressure 

 of steam at which engines are worked will be seen the im- 

 portance of having perfectly secure and suitable vessels to 

 contain a force of so destructive a power as steam. It does 

 not appear necessary to adopt a retrograde process, and re- 

 duce the pressure to 7 or 10 lbs. as that of former days. 

 On the contrary, it is desirable to prepare the public for a 

 still further increase of the working pressure if we are to 

 secure a satisfactory result of economy in the use of fuel. 



All these elements connected with steam, will, therefore, 

 have to be carefully considered in order to acquire a motive 

 power calculated to cheapen production in every stage of 

 our manufacturing process. This, it will be observed, can 

 be accomplished with perfect safety provided that boilers 

 are made on sound principles of construction, and accom- 

 panied with the use of sound material and good workmanship. 

 It must be borne in mind that the practice of boiler con- 

 struction, which at present exist cannot, in many cases, be 

 too severely censured, as these constructions demands the 

 skill of our best engineers, and the exercise of definite laws 

 founded on experimental research.* 



* It not unfrequently happens that some of the mill owners in the manu- 

 facturing districts are their own engineers, in which they frequently stipulate 

 for having their own proportions of steam engines, such as the diameters of the 



